1. Field of the Invention
This invention relates to dental instruments and, more particularly, to hand held instruments having an elongated handle fitted with a working tip at one end or with working tips at both ends.
2. Brief Description of the Prior Art
Dental hand instruments are typically fabricated with elongated handles of stainless steel, chromed brass, or aluminum having a round or octagonal cross section of about 1/4 inch diameter. Depending on the use of the instrument, the handle is fitted with a working tip of stainless steel, carbon steel, or other metal such as carbide at one end or with such working tips at both ends. Typical working tips include those employed in periodontics, hygienics and diagnostics such as curettes, scalers, probes, and explorers; in operatives such as angle formers, chisels, trimmers, excavators and carvers, and hatchet and hoe instruments; in endodontics such as dryers and spreaders and pluggers. A common factor in the use of instruments employing such tips is that the instruments must be gripped tightly and that the gripping fingers undergo repetitive movement while under substantial strain. Increasing symptoms of hand fatigue, cramping, strain and carpel tunnel syndrome are being reported with repetitive use of these standard instruments over extended periods of time, as is required in the daily practice of dentistry. The common practice of using latex gloves as protection may be a causative factor in the increase of these symptoms inasmuch as a hand held instrument is more difficult to manipulate with a gloved hand, perhaps requiring holding the instrument with greater force than would be required of a non-gloved hand. Use of latex gloves also reduces tactile sensitivity.
Increasing the diameter of the elongated handle from the standard 1/4 to 5/16 inch would appear to be indicated. However, increasing the diameter increases the weight of the instrument, adding to hand fatigue. Moreover, the resulting increase in weight dampens the tactile sensitivity of the working tip, leading to increased hand fatigue.
Some attempts have been made to substitute elongated plastic handles for the standard stainless steel handle. However such attempts have resulted in numerous problems such as an incapability to withstand sterilization procedures, resulting in one-use throw-away instruments. This inefficiency becomes even more significant in the case of double ended instruments since discarding loses the benefit of the remaining serviceability of both tips. The ability to provide replaceable tips and to choose any particular combination of tips is also lost. Poorly designed handle surfaces has resulted in increased hand strain and fatigue, undesirable handle flexibility and dampening of the tactile sensitivity of the working tip.